The invention relates to compounds of the formula I 
in which:
R1 is
1. (C1-C14)-alkyl,
2. (C2-C6)-alkenyl,
3. (C0-C6)-alkyl-(C3-C10)-cycloalkyl-(C0-C6)-alkyl, where the alkyl moiety is optionally substituted by one or more OH groups,
4. (C0-C6)-alkyl-(C6-C14)-aryl,
5. (C0-C6)-alkyl-(C3-C9)-heteroaryl,
6. (C2-C6)-alkenyl-(C6-C14)-aryl,
7. (C2-C6)-alkenyl-(C3-C9)-heteroaryl,
8. (C1-C6)-alkanoyl,
9. a radical as defined under 4., 5., 6. or 7., where the (C6-C14)-aryl or (C3-C9)-heteroaryl moiety is substituted by 1, 2 or 3 identical or different radicals from the group consisting of (C1-C10)-alkyl, carboxyl, amino, nitro, (C1-C4)-alkylamino, hydroxyl, (C1-C4)-alkoxy, where one to all hydrogen atoms can be replaced by fluorine atoms, (C6-C12)-aryloxy, halogen, cyano, di-(C1-C4)-alkylamino, carbamoyl, sulfamoyl and (C1-C4)-alkoxycarbonyl, or two adjacent radicals on the (C6-C12)-aryl ring together are alkylenedioxy, preferably methylenedioxy;
R2 is hydrogen, (C1-C10)-alkyl, (C0-C6)-alkyl-(C6-C12)-aryl or (C0-C6)-alkyl-(C3-C9)-heteroaryl, where the C6-C12-aryl or C3-C9-heteroaryl moiety is optionally substituted by 1, 2 or 3 identical or different radicals from the group consisting of carboxyl, amino, (C1-C4)-alkylamino, hydroxyl, (C1-C4)-alkoxy, halogen, cyano, di-(C1-C4)-alkylamino, carbamoyl, sulfamoyl and (C1-C4)-alkoxycarbonyl;
R3 is xe2x80x94Xxe2x80x94R4;
X is xe2x80x94Oxe2x80x94, xe2x80x94NR5xe2x80x94 or xe2x80x94Sxe2x80x94;
R4 is defined as R1;
xe2x80x83where R4 together with R2 can form a bridge member xe2x80x94CH2xe2x80x94CH2xe2x80x94 or xe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94;
R5 is hydrogen or (C1-C6)-alkyl;
A is a fused cyclic ring system which
a) is substituted by one, two or three, preferably by one or two, oxo or hydroxyl functions, where one hydroxyl or oxo function is in the neighboring position to the dihydropyran ring, and
b) is mono, di- or polysubstituted, preferably mono- or disubstituted, by a (C1-C10)-alkyl radical or a carboxyl group, where at least one alkyl substituent carries a functional group, such as hydroxyl, carboxyl or amino;
and physiologically tolerable salts thereof.